What Is VGA Cable?

By Jason Artman

VGA cables are a system of sending data from a computer to a monitor, allowing you to see the images displayed by your computer. They send information in an analog format, meaning that the video information is sent as an electrical signal and, as such, is subject to interference, harming the image quality displayed by the monitor. The VGA cable is a crucial component of many of the world's computers.


The VGA, or D-sub 15, cable is a 15-pin connector which separates all of the components of an analog video signal into individual cables for maximum signal integrity. It was developed as a replacement for the aging 9-pin DE-9 cable which was used to transmit 16-color EGA video signals in the late 1980s and early 1990s. Because the added pins reduced interference, VGA cables made it possible to display images with greater detail and less blurriness.


VGA cables produce the highest quality available from an analog display system and are used by all CRT computer monitors still in production. VGA cables can transmit images with millions of colors and at resolutions of 1600 by 1200 and higher. However, flat-panel LCD computer displays are becoming more commonly used, and because LCD displays are digital, a conversion must take place when they are connected to a computer using a VGA cable. Because of this conversion, an LCD display connected with a VGA cable can produce a blurry image. Purchase the best VGA cable that you can afford to minimize this effect.


VGA cables have been largely replaced by DVI cables in some computer systems. DVI cables transmit data digitally, producing a superior image. If your computer and monitor both support DVI cables, they should be used rather than VGA cables.


Adapters are available to convert VGA to DVI signals, allowing one type of monitor to be used with the other connection. These adapters ship with most new video cards. However, an analog-to-digital conversion takes place during this process, reducing image quality. Use DVI or VGA cables with no adapters whenever possible for the best display.


The 15-pin VGA cable and older 9-pin DE-9 cable are not compatible unless an adapter is used. DE-9 connections are still found in some older computers. Do not attempt to force a VGA cable into a DE-9 connection, as permanent damage to both the cable and computer will result.